The walls of M&J Video Games and Grand Slam Sports are lined with the obscure flotsam of the sports world, and hint at what rarer treasures are kept in safer quarters.

John Kelleher, who co-owns the store with his wife Mary, prides himself on finding elusive bits of paper, plastic and poly-resin that inspire upwellings of nostalgia in those who grew up with baseball cards and action figures instead of fantasy sports and 3D movies, or those searching to own their own piece of history, like the handwritten letter Kelleher says was signed by no less a national treasure than Jackie Robinson.

The Kellehers, whose original store is in Southington, will open their second retro video games and sports collectibles store this month in Newington on the Berlin Turnpike. The store’s name bears their initials — ‘M’ for Mary, ‘J’ for John.

The Newington store’s walls are covered with memorabilia signed, handled or otherwise imprinted by sports legends: a Miami Dolphins helmet signed by Dan Marino, a basketball signed by former NBA star Alan Iverson, baseballs flung by the sport’s greats. The motto of the store: “If you want it, we’ll get it for you.”

Though the Newington store has yet to officially open, a few people filtered in on a recent afternoon to sell Kelleher baseball cards.

“To come here and talk sports with people, see the old-school stuff and the new-school stuff, I love it,” he said. “I love everything to do with history.”

Kelleher, 48, got started in the collectibles business 40 years ago, when he was an 8-year-old hawking bits of junk at a weekend swap meet alongside his dad, a gold and silver salesman.

Over the years, buying and selling collectibles at weekend swap meets remained part of his weekend routine. In 2015, he heard that a sports memorabilia store in Southington was closing. He drove out, intending to buy the guy’s inventory, and ended up taking over his lease.

The Kellehers, who live in East Hartford, also started a store in Wallingford, but closed it earlier this year and moved its stock to Newington. They plans to hold a grand opening Friday through Sunday, with an appearance by Linda Tosetti, Babe Ruth’s granddaughter, whom Kelleher met years ago during a stint as mascot of the New Britain Rock Cats.

Mike Cannata, manager of the Southington store and a friend of Kelleher’s since he was 10 years old, said he’s seen younger people becoming interested in video game consoles that have been discontinued for 15 or 20 years — Super Nintendos, Sega Saturns and Dreamcasts.

“But when’s the last time you seen a 3-foot bobble-head?” he asked, gesturing to statuettes of Babe Ruth and Ted Williams that were, indeed, 3 feet tall.

Kelleher stocks his inventory with things bought or traded at swap meets and card shows, or brought in by customers.

His rarest treasure is a letter written by Jackie Robinson that was brought in by a customer a few months ago. It is addressed to a fan and mailed from the baseball legend and pioneer’s office. Kelleher said he verified the letter’s authenticity with experts and bought it from the customer. He believes it’s worth $12,000.

Kelleher sees the sentimental attachment people have to relics of their childhood. He suffers from it, too. “This whole store is my collection,” he said.

It is those rare moments when a customer stumbles on some token of youth that Kelleher treasures most.

“If you can get a customer a game or a card they’ve been looking for forever — you feel like you did something good,” he said.

During the summer, Cannata said, a woman found in their Southington store an action figure of an obscure Marvel superhero — Nightstalker — that she’d been looking for since she was 11 years old.

“She actually started crying,” he said. “I could see her eyes welling up. I was so happy for her.”

It is a point of pride for Kelleher and Cannata to find those small, physical monuments to childlike wonder. A card depicting their favorite ballplayer, a console they played as a child — these bits of paper and plastic have been left behind by the digital age, they believe, but not replaced.

“This business, it has its up and downs,” Cannata said. “But people are always going to come in looking for that special thing.”

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